Exhaust diffuser

ABSTRACT

ted length so that it is tuned to attenuate a predetermined sound frequency.

United States Patent Rutt [451 Aug. 22, 1972 [54] EXHAUST DIFFUSER 2,260,578 10/1941 Murray ..181/36.2 UX [72] Inventor; Paul Rutt, Jackson, Mich 763,221 6/1904 Ullom ..18l/47.2 [73] Assignee: Tenneco Inc., Houston, Tex. FOREIGN E S 0R PP ICATIONS [22] Filed: April 6, 1970 584,632 ll/ 1924 France l8 H56 [21] Appl Primary Examiner-Richard B. Wilkinson Assistant Examiner-John F. Gonzales [52] [1.8. CI. ..181/35 R, 181/41, 181/72 Attorney-Harness, Dickey & Pierce [51] Int. Cl. ..F0ln l/00, FOln 7/00 [58] Field of Search ..181/72, 36.2, 56, 60, 61, 57, [57] ABSTRACT 47 35 35 B; 29 An exhaust gas diffuser and acoustic element has an elongated tubular shape and is arranged horizontally [56] References Cited and transversely to the length of a motor vehicle while UNITED STATES PATENTS secured at the outlet end of the exhaust system to act as an acoustic component and a substitute for a tail- 3,348,629 10/1967 Cassel ..181/61 X pipe spout 1,867,802 7/1932 Bogert ..181/72 UX 2,618,355 11/1952 Hedrick ..181/57 3 Claim, 4 Drawing Figures EXHAUST DIFFUSER SUMMARY OF THE INVENTION It is the purpose of this invention to provide a component for use at the terminal end of an exhaust gas system for a motor vehicle internal combustion engine which extends transversely to the length of the vehicle and has a beneficial acoustic attenuation effect.

It is also an object of the invention to provide an acoustic component for the terminal end of an exhaust system which will in effect lengthen the exhaust system and thereby lower the natural frequency of the system.

It is also an object of the invention to provide an exhaust diffuser for the terminal end of an exhaust system which will displace the outlet for the system in a transverse direction.

The invention accomplishes the foregoing and other objects by means of an elongated tubular acoustic element which is attached at the terminal end of the exhaust gas system (i.e., to the end of the tailpipe) and which in its preferred form has an outlet means that is spaced transversely from the inlet to the element, the element being disposed horizontally at the rear of a vehicle with its longitudinal axis extending transversely to the tailpipe.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view in side elevation of a motor vehicle with an internal combustion engine having an exhaust system containing an acoustic component in accordance with this invention;

FIG. 2 is a perspective view in simplified form of the acoustic element of FIG. 1;

FIG. 3 is a perspective view, with one end in section, of a modified form of acoustic element; and

FIG. 4 is a plan view of another form of acoustic element.

DESCRIPTION OF THE INVENTION A motor vehicle fragmentarily shown at 1 has an internal combustion engine 3 mounted therein at the forward end of the vehicle. The engine has an exhaust manifold 5 that discharges exhaust gases into an exhaust pipe 7 which forms the upstream end of the exhaust gas flow and silencing system 9. The exhaust pipe 7 carries the gases to a muffler 11 of any desired construction which functions to remove most of the objectional sounds from the exhaust gas passing through it. The muffler 11 is connected to a tailpipe 13 which carries the gases to the rear of the vehicle for discharge to the atmosphere. In accordance with the present invention, an acoustic element 15 is mounted on the terminal end of the tailpipe 13 by way of its inlet bushing 17 which is secured by clamp 19 to the tailpipe.

The element 15 is in the form of a hollow cylindrical or tubular element 21 which is entirely closed except for the inlet 17 and a pair of outlet conduits 23 and 25 which are located adjacent opposite ends of the tubular body 21 and preferably directed downwardly toward the ground when the element 21 is mounted on a vehicle. While the location of the inlet 17 will depend in the first instance on the transverse location of the tailpipe 13 it is preferable that it be as close to the midpoint of the length of the element 15 as possible. As indicated in FIG. 1 the element 15 is mounted so that it is horizontal and its axis transverse, preferably at right angles, to the longitudinal axis of the exhaust gas system 9 and in particular to that of the tailpipe 13.

By virtue of being fitted with the two outlets 23 and 25 the element 15 gives an outward appearance of a dual exhaust system and therefore has special appeal for certain drivers. It will be observed that the length of the exhaust system 9 is increased over what it would be if the tailpipe 13 merely opened to atmosphere inasmuch as the gas is required to travel the required distance from the inlet 17 to one-or the other of the outlets 23 or 25. The increase in length therefore lowers the natural frequency of the system and in some cases will drop objectionable frequencies below the audible range. The empty space within the shell 21 can also serve as a relatively large Helmholtz resonance volume which will act to attenuate objectionable sounds over a fairly broad range of frequencies. In addition, the element 15 serves to eliminate run-down pop.

The specific construction of the element 15 may take various forms as indicated by the structure of FIG. 3 wherein an acoustic component 31 having dual inlets 33 and 35 is attached by means of a Y-pipe 37 and clamp 39 to the end of the tailpipe 13. In this form of component the horizontally and transversely disposed tubular shell 41 has a slot extending longitudinally along the bottom side as provided by the spaced flanges 43 and 45 to provide an outlet means 47. Thus, gas from the tailpipe 13 is divided into two streams by the Y-pipe 37 to enter inlets 33 and 35 and be diffused throughout the length of the shell 41 and leave the muffler through the slotted outlet means 47. The muffler functions similarly to the unit 15 in that it along with the Y-branch 37 lengthens the exhaust system and the space within the shell 41 provides a Helmholtz volume effect for attenuating objectionable sounds including run-down pop.

The construction of FIG. 4 differs somewhat in principle from the units 15 and 31 though the structure is similar. In this case, the component 51 has a hollow elongated shell 53 with an inlet 55 that is attached to the end of the tailpipe 13, the shell having an outlet 57 which is preferably aligned longitudinally with the inlet 13 though displaced angularly so as to be, preferably, directed downwardly. The length of the shell 53 is preselected so that the distance between the inlet and outlet and the end 59 of the shell is approximately onequarter of the wave length of an objectionable frequency to be silenced so that the unit 51' functions as a Quinkie or quarter wave length tuning tube.

Modifications may be made in the specific structure shown without departing from the spirit and scope of the invention.

I CLAIM:

1. An acoustic element for use as the terminal end of a motor vehicle internal combustion engine exhaust gas flow and silencing system comprising a closed tubular empty body having a longitudinal axis, said body having a substantially aligned inlet and outlet extending at substantially right angles to said longitudinal axis and the space in the body located transversely of said inlet and outlet being of a selected length so that it is tuned to attenuate a predetermined sound frequency.

2. In an exhaust gas flow and silencing system for a vehicle mounted internal combustion engine, a gas flow conduit extending longitudinally of the vehicle and having an inlet end for connection to said engine and an outlet end located adjacent the rear of the vehicle, silencing means in said conduit located upstream of said outlet end, a tubular outlet diffuser member having an inlet means connected to and receiving gas from said outlet end, said tubular member extending transversely to the longitudinal direction of said conduit, said tubularmember having gas outlet means therein, said outlet means comprising an opening in the tubular member substantially aligned longitudinally with said member inlet means, the space in said member located transversely of said inlet means and outlet means being of selected length so that it is tuned to attenuate a predetermined sound frequency in the system.

3. In an exhaust gas flow and silencing system for a vehicle mounted internal combustion engine, a gas flow conduit extending longitudinally of the vehicle and having an inlet end for connection to said engine and an outlet end located adjacent the rear of the vehicle, silencing means in said conduit located upstream of said outlet end, and empty tubular outlet diffuser member closed at opposite ends and having an inlet means connected to and receiving gas from said outlet end, said tubular member extending transversely to the longitudinal direction of said conduit, said tubular member having gas outlet means therein, said outlet means comprising a pair of spaced outlet conduits located transversely on opposite sides of said member inlet means and having axes substantially parallel to each other and normal to the axis of the diffuser member. 

1. An acoustic element for use as the terminal end of a mo
 2. In an exhaust gas flow and silencing system for a vehicle mounted internal combustion engine, a gas flow conduit extending longitudinally of the vehicle and having an inlet end for connection to said engine and an outlet end located adjacent the rear of the vehicle, silencing means in said conduit located upstream of said outlet end, a tubular outlet diffuser member having an inlet means connected to and receiving gas from said outlet end, said tubular member extending transversely to the longitudinal direction of said conduit, said tubular member having gas outlet means therein, said outlet means comprising an opening in the tubular member substantially aligned longitudinally with said member inlet means, the space in said member located tranSversely of said inlet means and outlet means being of selected length so that it is tuned to attenuate a predetermined sound frequency in the system.
 3. In an exhaust gas flow and silencing system for a vehicle mounted internal combustion engine, a gas flow conduit extending longitudinally of the vehicle and having an inlet end for connection to said engine and an outlet end located adjacent the rear of the vehicle, silencing means in said conduit located upstream of said outlet end, and empty tubular outlet diffuser member closed at opposite ends and having an inlet means connected to and receiving gas from said outlet end, said tubular member extending transversely to the longitudinal direction of said conduit, said tubular member having gas outlet means therein, said outlet means comprising a pair of spaced outlet conduits located transversely on opposite sides of said member inlet means and having axes substantially parallel to each other and normal to the axis of the diffuser member. 